1. Field of the Invention
The present invention relates to a laminate of an aromatic liquid-crystalline polyester film and a metal, and a tape automated bonding (TAB) tape, film condenser and printed wiring board using the same.
2. Description of the Related Art
Recently, with increasing requirements for light weight and small size electric and electronic parts in the market, demands for laminated substrate of resin films and metals such as TAB tapes, film condensers, rigid, flexible both-sides printed wiring boards and the like are being enlarged. As the raw materials of these laminated bodies of resin films and metals, generally used are polyphenylene sulfide and polyimide resins, however, they have problems that electric properties are not necessarily sufficient, water absorbing property is high and the like.
Therefore, there are developments on laminated substrates of aromatic liquid-crystalline polyesters and metals having low water absorbing property and excellent electric properties.
For example, JP-A Nos. 61-130041, 2-252738, 3-183185 and 5-42603 disclose methods of crimping a metal foil and a liquid-crystalline polymer film produced by an extrusion or inflation molding process. However, the liquid-crystalline polymer film produced by an extrusion or inflation molding process shows poor film forming processability due to large anisotropy and cause deformation of the film, namely, abilities of this film cannot be accepted as satisfactory because of such problems.
An object of the present invention is to provide a laminate of an aromatic liquid-crystalline polyester film and a metal, having excellent processability due to small anisotropy while keeping excellent electric properties.
The present inventors have intensively studied to find laminated substrates having no problems as described above, and resultantly found that a laminate of a liquid-crystalline polymer film and a metal obtained by a casting method has excellent processability due to small anisotropy while keeping excellent electric properties, leading to completion of the invention.
Namely, the present invention relates to a laminate obtained by dissolving an aromatic liquid-crystalline polyester in an organic solvent to obtain a solution, casting the solution and removing the solvent to give a film, and laminating the film with a metal layer.